Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
ME-SFI lambda control, function engine 272 - GF07.61-P-4022V
ENGINE 272.942 in MODEL 171
ENGINE 272.963 in MODEL 171
Shown on engine 272
The mixture composition is maintained within limits as close as possible to λ=1 in order to achieve a high conversion of the exhaust gases in the catalytic converter.
The O2 sensors detect the oxygen share in the exhaust and transmit corresponding signals to the ME-SFI [ME] control unit. This changes the mixture composition so that in all engine operating statuses, the desired oxygen (usually λ=1) is set.
This procedure is repeated (control loop), the control speed is dependent on engine load and speed.
The lambda closed-loop control is operational in the following operating conditions (closed-loop control):
- Coolant temperature < approx. -10°C,
- Blocking time after starting expired
- O2 sensors upstream TWC have reached operating temperature
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.